Method of and apparatus for making knurled socketed screws



, Oct. 18, 193 8. w. A. PuRTr zLl.

FIG 6 WILLIAM A. PURTELL INVENTOR m ATTbR .EY.

. 30 with Patented Oct. 18,1938 7 i 2,133,466

METHOl) OF AND APPARATUS FOR MAKING KNUBLED SOCKETED SCREWS William A. Purtell, West Hartford, Conn., asaignor to The Holo-Krome Screw Corporation, a corporation of Connecticut Original application June 15, 1935, Serial No. 26,861.- Divided'and this application April 7, 1937, Serial No. 135,506

25 Claims. (Cl. Ill-'10) My invention relates to methods of and aptwo operationsastaughtinmy patent mentioned, paratus for making knurled socketed strews. to produce a tapered head 2, a crowned top 3 It has among its objects to provide an imand an elongated shank 4. This blank is then proved method of, and improved apparatus for, socketed by a punch 5, while the blank is dis- 5' making such knurled socketed screws. A furposed in a socketing die Ii 01' an improved con- 5 ther object is to provide such an improved struction, all in such manner as to form my method of and apparatus for making such imimproved knurling on the finished product as proved screws as described and claimed in my shown in Figure 6, including the knurled or copending application Serial No. 26,861, filed fluted portion 1 on the cap screw head 8 dis- 10 June 15, 1935, of which this application is a posed below the outer smooth closing-oi! band 9 l0 division. Other objects of my invention are to on the head 8. enable knurled screws to be made in an im- Referring more particularly to Figures 1 and 3, proved quick and inexpensive manner bringing it will be noted that the socketing die S'is prothe cost of making the same down substantially vided with a fluted knurl forming socketing aperto the cost of making ordinary unknurled screws ture I0. This corresponds in conformation to 15 and, more particularly, to enable, the screws to the knurled portion I on the head 8 of the screw be knurled while the screw is being socketed, heretofore described, and has radially-located in such manner as to eliminate all necessity for flute forming rib and groove portions i i and additional knurling or handling operations 'i'oli2 thereon, corresponding to and forming like lowing socketing, and also to enable these screws but oppositely disposed portions of the flutes 20 a to be produced with existing-equipment with only on the knurled or fluted portion 1 of the finslight changes and without appreciable addiished screw. Further, it will be noted that the tional expense. These and other objects and rib portions ll each have sloping sides convergadvantages of my improvements will, however, ing into a vertical edge and that they extend hereinafter more fully appear. inwardly from the wall of the aperture Ill be- 25 In the accompanying drawing, I have shown low an annular smooth portion I 3 and are profor purposes of illustration certain forms in vided at their upper ends with downwardly slopwhich' my improved method may be practiced ing portions l4 which lead from the wall of the and of the apparatus used in connection thereportion i3 over the upper'ends of the flutes to the inner edges thereof. Further, it will be In the drawing:- noted that the bottoms oi the grooves between Figure 1 is a vertical sectional view of a socketthe ribs ii, herein indicated at II, are of the ing die and punch simultaneously knurling and same diameter as the portion l3 above the same. socketing a blank in accordance with my im- Also, it will be observed that the socketing die provements; aperture III is herein provided with a blank sup- 35 Fig. 2 is a side elevation of a blank used; porting portion on its bottom and with a reduced Fig. 3 is a vertical section through the socketextension i5 thereon adapted to receive the ng die; shanks 4 of the blanks, and that a knock-out pin Fig. 3* is an enlarged detail of the tops of the i6 is provided in this extension IS in order to flute forming means; support the shanks and push up the finished 40 Fig. 4 is a transverse sectional view of the screws to eject the same. die on line 4-4 of Figure 3; Thus, with the blank i suitably positioned in Fig. 5 is a sectional view similar to Figure 4, the socketing die 6, when the punch 5 enters. showing a modified form of die; and the upper end of the blank to socket the same, Fig. 6 is a side elevation partially in section, 1. e., form the socket ll of the finished screw, 45 showing the knurled cap screw produced. I am able simultaneously to form on the screw In carrying out my improvements, I preferthe smooth upper closing-oiLrim portion 9 and ably utilize the preferred method of and apparathe lower knurled portion 1, previously described. tus for making cap screws taught in my previous This is done all in one operation, and as the Patent No. 1,978,372, and certain improvements metal displaced by the punch 5 flows laterally 50 in connection with both, whereby the same are from in advance of the punch and is distributed adapted to the production of knurled cap screws thereby to fill out the die aperture III in the of the socketed type. manner described and claimed in my previous The blank, generally indicated at i. in Figure patent mentioned. More particularly, it will 2,,is first prepared, preferably by upsetting in be noted that as the socket ii is formed in the screw,

the metal in the blank is caused to enter the grooves l2 in the socketing die and to be so shaped by the portions H, l2, l3 and ll of the latter die, as to produce the desired knurled portion 1 and upper sealing of! band 9, by the time the punch 5 has completed the formation of the socket l'l, whereupon obviously the completed screw may be removed in the usual manner by pushing up the knock-out pin ii.

In Figure 5, it will be noted that the shape of the rib and groove portions on the die 6 is-somewhat modified. Here, the ribs, corresponding to the ribs II, are indicated at I! and have wider tops, while the" grooves, corresponding to the grooves l2,'are indicated at l8, and substantially wider than the ribs l8. It will, of course, be evident that, with the socketing die aperture changed to conform to the new ribs and grooves, screws will be made by the same general method and apparatus heretofore described; the principal difference being that, in this construction, a modified form of knurl is produced which presents to the fingers a more smooth rib surface than that previously described and one with greater spaces between the ribs.

It will be understood that while I have shown only a blank and a socketing die and the socketing punch, I contemplate theformation of the blank by upsetting, as previously described in my patent mentioned, and further that I contemplate the use of my improved socketing die and punch in connection with'elther a separate socketing machine or a mechanism adapted to perform both the upsetting and the socketing operations successively and automatically in the same machine.

As a result of my improvements, it is made possible to form the knurling on the screw in such manner as, not only to produce an improved knurled screw, but very substantially to reduce the cost of producing such screws. Further, it is made possible to eliminate altogether the separate knurl forming operation heretofore. necessary, including the resultant additional handling of the screws, while alsoeliminating the need for providing additional apparatus. Also, it will be evident that it is possible to carry out my invention while practising my previous method and using my previous apparatus with only minimum changes and without requiring material increase in expense. These and other advantages of my improvements will, however, be clearly apparent to those skilled in the art.

' while I have in this application specifically described certain forms of my invention, it will be understood that these have been used for purposes of illustration, and that the same may be modified and embodied in other forms without departing from its spirit or the scope of the appended claims. I

what I claim as new and desire to secure by Letters Patent is:-

1. The step in making knurled socketed screwswhich consists in, knurling the screw while forming a socket in the same.

2. The step in making socketed cap screws which consists in, working the periphery of the head of the blank to form a roughened exterior while forming a turning socketin the head.

3. The step in making knurled socketed screws which consists in, knurling the blank while expanding the external diameter thereof and forming a turning socket in the blank.

'4. The step in making knurled socketed screws which consists in, forming superimposed knurled 7. The method of making knurled socketed screws which consist in, socketing the blanks, and knurling the exterior thereof while forming the inner and outer walls of the socketed portion.

8. The method of making knurled socketed screws which consists in, forcing a blank into a die while socketing the blank, and forming longitudinally extending knurls on the periphery of the socketed portion as the socket is being formed.

9. The method of making knurled socketed screws which consists in, forcing a blank into a die while socketing the blank, and forming longitudinally extending knurls on the periphery of the socketed portion as the socket is being formed and while simultaneously forming a smooth upper sealing on band above the knurled portion.

10. The method of making knurled socketed screws which consists in, forcing a blank into a die while socketing theblank, forming longitudinally extending knurls on the periphery of the socketed portion as the socket is being formed, and moving the socketed screw reversely in the die to eject it therefrom.

11. The method of making. knurled socketed screws which consists in, forming a wide knurled lower portion and a relatively narrow upper smooth band portion thereon as the screw is socketed in a socketing die aperture having a fluted lower portion and a smooth upper portion, and ejecting the screw upward therefrom following knurling. I

12. The method of making knurled socketed cap screws which consists in, partially forming the head on the blank, and knurling the head while forming .the inner and outer walls of the socketed head.

13. The method of making knurled socketed screws which consists in, upsetting the blank to form the head, and knurling the upset portion thereof while forming the internal and external walls of the socketed portion.

14. Apparatus for knurling screws including a die haying a screw socketing aperture and knurl forming means on the wall of a portion of said aperture and connected to an end smooth portion of said aperture by an intermediate longitudinally grooved tapered portion.

15. Apparatus for knurling screws. including a die having a screw socketing aperture and knurl forming means on the walls of said aperture comprising vertically disposed flutes having sloping ends leading'to the inner edges of said flutes.

16. Apparatus for knurling screws including a die having a screw socketing aperture comprising spaced portionsof uniform cross section, one smooth and the other serrated, and an intermediate tapered portlon opening into said serrated portion, and a punch cooperating with said die and a blank therein to form a socket in said blank in said aperture while said serrated portion knurls the exterior of said blank.

17. Apparatus for knurling screws including a die having a screw socketing aperture comprising spaced portions of uniform cross section. one

smooth and the other serrated, an intermediate tapered portion opening into one end of said serrated portion, and a blank supporting portion at the opposite end of said serrated portion.

18. Apparatus for knurling screws including a die having a screw socketing aperture and knurl forming means on the walls of said aperture comprising vertically disposed flutes toward the bottom oi. said walls and a smooth portion at the top of the latter.

19. Apparatus'ior knurling screws including a die havinga screw socketing aperture and knurl forming means on the walls of said aperture comprising vertically disposed flutes toward the bottom of said walls and a smooth portion at the top of the latter, said smooth portion being of substantially the same diameter as the grooves between said flutes.

20. Apparatus for knurling screws including a die having a screw socketing aperture and knurl forming means on the walls of said aperture comprising vertically disposed flutes toward the bottom oi said walls and a smooth portion at the top of the latter, said fluted portion being substantially wider than .said smooth portion.

21. Apparatus for knurling screws including a die having a screw socketing aperture and knurl forming means on the walls of said aperture comprising vertically disposed flutes toward the bottom of said walls and a smooth portion at the top oi the latter, said flutes having inclined portions on their upper ends leading from saidsniooth portion and the inner edges of the flutes.

22. Apparatus for knurling screws including a die having a socketing aperture and knurl forming means in the walls of said aperture, and a cooperating punch cooperating with said die and a blank therein to form a socket in a blank in said aperture as said knurl forming means knurl the periphery of the blank.

23. Apparatus for knurling screws including a die having a socketing aperture, a punch cooperating with said die and a blank therein to form a socket in said blank in said aperture, and knurl forming means for knurling the periphery of a blank as said punch acts on a blank in said aperture.

24. Apparatus for knurling screws including a die having a sccketing aperture, a punch cooperating with said die and a blank therein inform a socket in said blank in said aperture, and knurl forming means for knurling the periphery of a blank as said punch acts on a blank in said aperture, said .last mentioned means comprising flutes in said aperture having tapered extremities on their receiving ends and spaced between the opposite ends of said aperture.

25. Apparatus for making fluted cap screws comprising a socketing die having the lower portion of the walls of its socketing aperture longitudinally fluted and also having a smooth por-. tion above said fluted portion, and a punch for simultaneously socketing a tapered blank in said socketing aperture and forcing the metal in said blank into said fluted and smooth portions of the walls during socketing.

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